Another reason why burn rates.....

[rwsmith]

Here is another reason why powder burn rate charts are useless. Looking at about a half a dozen charts sometimes Red Dot is 5 places or more faster than Bullseye and in other charts their places are reversed. I had confidence that at least the RELATIVE positions were correct, but now I don't believe much of anything a burn rate chart tells me.

I'm fairly confident that BE is faster than Red Dot and that's all I need to know, thankyouverymuch.

 

[alwslate]

Powders sometimes behave differently in different cartridges. I have
read that BE is faster than RD in shotshells but the order is reversed
in pistol cartridges. Older Alliant data usually shows lighter charges
for RD than BE at similar pressures in handgun loads.

 

[BLUEDOT37]

Burn rate tables

I'm with you. They give me a headache trying to compare tables.

From what I gather, it's the test vessil size they burn it in that causes the relative differences. There might be more too but I can't recall right now.

.

 

[Fishinfool]

I never take powder burn rate charts as gospel. I do find they are handy when trying a new powder, using the chart to narrow down powder choices when comparing with a known powder for the load I am seeking.

Larry

 

[Forrest r]

I look at reloading data for the larger capacity cases to confirm how fast a powder burns. Faster powders tend to use less powder than the slower powders.

It consistently takes more bullseye than reddot for max loads in the:
357
44mag
40s&w
45acp

Heck the 38spl & 9mm use more bullseye than redot.

 

[JBnTx]

Here is another reason why powder burn rate charts are useless...

One problem is how the burn rate charts are constructed.

Powders #4, #5, #6 and #7 could have all the exact same burn rate, but as they're listed you might think #4 is faster than #7, when it's not.

There could be a very small difference in burn rates between #10 and #11, but a massively huge difference between #12 and #13.

A burn rate chart only tells you where a powder fits in with ALL the other powders, not the one next to it in line.

 

[Engineer1911]

I use powder burn rate charts to help determine a 'Starting Load'. I got one of those 'great deals' on a jug of Power Pistol powder. All the internet info I could find along with limited reloading data indicated that this was a "superb" powder with 'user friendly' characteristics.

My experience was sharp recoil, incredible muzzle blast compared to my usual powders, and not exceptionally clean burning. Brass ejection was consistent without sticking, normal primer appearance, and appropriate velocity. I'm glad the jug is empty. But the price was right ! ! !

 

[Jellybean]

I'm with you. They give me a headache trying to compare tables.

From what I gather, it's the test vessil size they burn it in that causes the relative differences. There might be more too but I can't recall right now.

.

Correct, the burn rates vary depending on the size and shape of the container they are used in. The testing that the charts are made from are done in a "bomb", which is a round, steel ball shape that is totally enclosed. As you put them in cylindrical tubes of various sizes and profiles with an open end their is no way to tell what order they are in. Burning rates can also be changed by the amount of powders used in a given container because of their individual characteristics and effects of increasing pressure. This is why most reputable sources tell you not to use them to work up loads or to choose powders for any certain application.

Just like the manuals themselves, they are nothing but a little bit of information that is intended to guide the reloader in the right direction, but requires more information to actually make it useful. They are not the "chiseled in stone" facts.

 

[johngalt]

Lot to lot variations could also shuffle the order around. Alliant used publish the burn rates relative to bullseye.

For example, the used to list red dot as about 94% as fast as bullseye, green dot was 79%, unique around 66%, etc.

What gets me is alliant must have 5 or 6 shotgun powders that are all about the same burn rate as red dot. I don't really understand the point f that.

 

[muddocktor]

I kind of like the way Accurate does their burn rate chart as compared to others. Instead of giving a numbered list, they have a spreadsheet looking chart with all the common powder manufacturers listed across the top and relative burn rates going from fast to slow vertically. Where the burn rates between the different powders are similar, they will be listed in the same horizontal line under the manufacturers column.

Here's a link - Link to pdf page

 

[OKFC05]

I use powder burn rate charts to start a fire in the fireplace. That's about all you can count on them being good for, for a certainty.

I want to see a LOAD CHART done with my cartridge in an instrumented pressure barrel, preferably with my exact bullet, or at least something very similar.

Having studied advanced calculus, I was able to wade through the second order differential equations that govern internal ballistics, and having done so, I suspect the manufacturers only publish generic burn rate charts for historical reasons dating back several hundred years, when we did not have modern pressure testing equipment. There is a nebulous relationship, at best, between a closed "bomb" and a modern cartridge shape.

Closed "bomb" pressure tests were all the rage 200 years ago when there were dozens of different black powder sources, made to who knows what standard, if any. Each source of powder and fuzes had to be tested and calibrated before using in your cannon if accuracy and reliability were to be had. The Confederates at Gettysburg were hampered by using a new uncalibrated batch of "improved" cannon ammo that shot over the Federal line and exploded harmlessly behind them.

 

[Nevada Ed]

I have used Bullseye, Red Dot and e3 in 12 Ga. target and light
hunting loads.
Have used all three in the 38 special and the 9mm Luger, also.

Bullseye is at its best with target loads but can reach top end
38 or 9mm loads, notice I did not state +P loads.
Red Dot can reach higher fps than Bullseye in the 38 and 9mm
cases but its volume limits it to higher speeds in the little 9mm.

There is no data in pistol/revolver with e3, so I will leave this alone.

Burn rate is nice to look at but it would also be nice to know
how each powder reacts at it maximum loadings !! Do they
just gradually build pressure or do they turn into a "Bomb"
with the last few grains of powder?

I have found out over the years that burn rate is just part of the story.
One reason I am glad to have a 357 K and L frame to test out the little 38 special
loads, near maximum. Some powders can be an eye opener !!

 

[ArchAngelCD]

At least 2 posts talk about Bullseye being used in shotgun shells. I didn't know Bullseye could be used in shotgun shells, where do you get the data?

 

[BigBill]

I don't worry about handguns but the semi auto military rifles require the burn rate of imr 4895 for the correct cycle timing.

For handguns it's unique for leadcast and 2400 for jacketed.

 

[OKFC05]

I don't worry about handguns but the semi auto military rifles require the burn rate of imr 4895 for the correct cycle timing.

For handguns it's unique for leadcast and 2400 for jacketed.

This is what they use for 4895 in the M1, not some burning rate number. Modern pressure test equipment can plot the whole chamber pressure curve, plus measure port pressure. During the critical last .2 milliseconds, too high a pressure in the barrel will drive the port pressure above 10,000 and batter the action. Too little pressure, it may not cycle.

 

[rwsmith]

You guys are right.....

There are just too many variables that aren't included. I shouldn't have said "completely useless' but 'almost completely useless'. The only thing I've gotten from them is, "is this powder slow, medium, or fast?"

 

[BigBill]

In the Egyptian Hakim this semi auto requires the correct gun powder.

 

[johnnymg]

I agree that burn rate charts/comparisons are not very illuminating.

As an example, Universal and Power Pistol are neighbors on the burn rate chart yet work VERY differently in my GAP loads. The Uni (which works fine 40 S&W) is more than 100 FPS slower than Power Pistol at max load levels. The StDev is also a lot more with the Uni.

I like Uni for my 9mm and 40 but NOT for the GAP!

 

[alwslate]

At least 2 posts talk about Bullseye being used in shotgun shells. I didn't know Bullseye could be used in shotgun shells, where do you get the data?

Older Alliant and Hercules manuals. Loads are listed for 1 oz
of shot only. I have loaded and shot many thousands of 1 oz
loads with BE for Trap shooting, have gone through many 8 lb
jugs. Near the bottom of 8 lb jug labels it says " great for
light 12 ga loads". My standard 1 oz load uses a Green
Duster wad, 16 grs BE, Win 209 primer and 1 oz 7 1/2s.

 

[ArchAngelCD]

Older Alliant and Hercules manuals. Loads are listed for 1 oz
of shot only. I have loaded and shot many thousands of 1 oz
loads with BE for Trap shooting, have gone through many 8 lb
jugs. Near the bottom of 8 lb jug labels it says " great for
light 12 ga loads". My standard 1 oz load uses a Green
Duster wad, 16 grs BE, Win 209 primer and 1 oz 7 1/2s.

Live and Learn, thank you...